As is well known, a cigar lighter comprises a lighter body which is secured on a fixed wall of the vehicle, such as a console or the fascia of the latter.
This body, firstly, carries electrical power supply components together with a current take-off member which is usually in the form of a bimetal strip, and, secondly, serves as a receptacle for the removable heating plug, which comprises two parts, one of which is movable axially with respect to the other against the action of axially acting resilient return means, in the manner which is described for example in the document FR-A-2 701 438.
More precisely, the movable part comprises a knob made of electrically and thermally insulating material, which is fixed to an electrically conductive support member that carries, and is insulated from, a terminal shroud which receives within it an electrical heating resistance of spiral form.
When the knob is pushed in, the shroud comes into engagement with the hooks of the current take-off bimetal strip, and an electrical circuit is set up which causes the heating resistance to become hot.
Once the said resistance reaches the desired temperature, the leaves of the bimetal strip dilate, and the knob reverts to its initial position under the action of the resilient return means. It then only remains for the plug to be removed, for a cigarette, for example, to be lit.
It is therefore important to obtain a reliable mechanical and electrical connection between the outermost turn of the spiral of the heating resistance and the inner wall of the shroud that receives the heating resistance.